Composition of meat in La Belle and White Plymouth Rock chickens, slaughtered at different age

Т. Popova*, E. Petkov, M. Ignatova

Institute of Animal Science, 2232 Kostinbrod, Bulgaria
(Manuscript received 16 May 2015; accepted for publication 8 June 2016)

Abstract. An experiment with two lines of chickens – synthetic line La Belle and White Plymouth Rock was carried out in the Institute of Animal Science, Kostinbrod to assess the meat quality in regards to chemical composition and the fatty acid profile at the age of 9 and 18 weeks. The age affected the lipid content which decreased significantly in breast (p<0.05) and thighs (p<0.01) in the older chickens of both lines. The content of protein and moisture in breast differed between the lines (p<0.05), showing higher protein and lower moisture in White Plymouth Rock chickens, while in the thigh muscles the line and age significantly interacted (P<0.001) in regards to these traits. Interactions between the two factors (p<0.01) was observed for the ash content in the breast, whereas in the thighs it tended to decrease with the age in both lines. The fatty acid composition of the meat was influenced mainly by the age of the chickens. The total content of the saturated fatty acids was increased in the thighs of the older birds (p<0.01), while the proportion of the monounsaturated fatty acids was decreased in the breast (p<0.01) and thighs (p<0.001) with advancing age of the chickens. The opposite was observed for the content of the polyunsaturated fatty acids in the breast, which increased at higher age of slaughter (p<0.001). In thigh meat, the changes of the polyunsaturated fatty acids induced by age followed the same pattern, however significant interaction with the line was observed (p<0.05). The cholesterol content in the breast differed significantly between the two lines (p<0.05) and reduced with age (p<0.001). In the thighs considerable decrease (p<0.001) of the cholesterol was observed in La Belle birds.


Heavy metal content in the meat of common carp (Cyprinus carpio L.) and rainbow trout (Oncorhynchus mykiss W.), cultivated under different technologies

St. Stoyanova*, I. Sirakov, K. Velichkova, Y. Staykov

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 15 October 2015; accepted for publication 19 February 2016)

Abstract. Water pollution from industrial production and developing agriculture is a serious problem in aquaculture. The aim of this study was to determine the content of heavy metals Zn (zink), Pb(lead), Ni (nickel) and Cd (cadmium) in the muscles of common carp (Cyprinus carpio L.) and rainbow trout (Oncorhynchus mykiss W.), grown under different technologies. In the current study were investigated common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss), cultivated in net cages, earthen ponds and raceways. The concentration of heavy metals in the muscles of fish was determined by the methods of AAS in the Scientific laboratory of the Faculty of Agriculture. The influence of different production technologies on the bioaccumulation of Zn, Pb, Ni and Cd (in the flesh of common carp and rainbow trout) was found. The Ni content in muscles was 31.25% higher in common carp, cultured at earthen ponds, compared with its content in the flesh of the fish raised in net cages. The concentration of Pd and Ni in rainbow trout, raised in raceways was higher than that determinated for rainbow trout cultivated in net cages, by 25.0% and 7.14%, respectively. The concentration of Cd and Zn of these species, grown in raceways were lower by 33.33% and 2.14%, respectively, compared with their concentration in rainbow trout, cultivated in net cages.


Extraction and characterization of anthocyanin colorants from plant sources

S. Dyankova*, M. Doneva

Institute of Cryobiology and Food Technologies, 53 Cherni Vrah, 1407 Sofia, Bulgaria (Manuscript received 2 November 2015; accepted for publication 19 January 2016)

Abstract. Natural pigments (and especially those of anthocyanins) are a valuable source of bioactive compounds and may be used in the production of new functional food ingredients. Furthermore, their applications in the treatment and prevention of chronic disorders are becoming more and more widespread. In the last few years consumers have focused their attention on the natural biologically active compounds as functional food ingredients, and therefore, it may be assumed that natural colorants are an alternative source of synthetic additives. The aim of the study was to determine the quantitative content of monomeric anthocyanin pigments in extracts obtained from eight plants. The total content of monomeric anthocyanin pigments was measured by a pH-differential method. The TLC analysis of the pigment extracts from the different plants showed intensive rose, red and violet stripes corresponding to the anthocyanin content. The extracts from chicory and lavender petals were unstable and their color decreased in intensity in 1 month. The analysis of the experimental data shows that the yield of pigment substances depends on a few factors: the type of plant, the preliminary treatment of the plant and the solvent that is used. The largest quantity of extracted substances in the studied plants were isolated from chokeberry (2 195.9 cyd eq mg/l), followed by blackberry (1 466.2 cyd eq mg/l) and one variety of the grapes (1 199.3 cyd eq mg/l). In the case of chokeberry, the pigment content included a large number of anthocyanins and the combination of these components was the reason for the deep red/violet color of the extract. Fresh or frozen materials are the most suitable for extraction of anthocyanin pigments. On the whole, fruit pulp yielded a larger quantity of pigments than juice. Anthocyanins are water-soluble compounds and for that reason their isolation requires water and other polar solvents. Better stabilization of color is obtained by a slight acidification of the solvent with diluted hydrochloric acid. Due to the high content of organic acids in fruits, this effect is attained in a natural way.


Effect of dietary vitamin E supplementation on the oxidative stability of lipids and proteins in cooked pork

T. Popova*, P. Marinova, M. Ignatova

Institute of Animal Science, 2232 Kostinbrod, Bulgaria

Abstract. The changes in the lipid and protein oxidative stability in m. Longissimus dorsi (m. LD) and m. Semimembranosus (m.SM) in response to vitamin E supplementationinthediet(400mg/kgfeed)andcookingwerestudiedin♀Younax♂Pietrainpigs. Musclesampleswerecookedat100°Cfor30minutes.

Lipid oxidation was analysed by determination of 2-thiobarbituric acid reactive substances (TBARS) and the oxidation of proteins was determined by measuring the content of carbonyls in muscles before and after cooking. Dietary vitamin E supplementation in pigs affected significantly the lipid oxidative stability by reducing the content of TBARS in fresh and cooked samples of m. LD (p<0.01) and m.SM (p<0.001). Protein oxidation was not significantly influenced by vitamin E, although the carbonyl contenttended to be lower in the samples of m. SM in the supplemented pigs. In both muscles oxidative stability was affected by the high temperature showing significantly increased contents of TBARS (p<0.001) and carbonyls in cooked samples, regardless of presence if vitamin E in the diet.


Influence of the sweet red paper extract on the quality and oxidative changes in fats of sausages

А. Kuzelov1*, V. Ilieva2, N. Taskov3, D. Saneva3

1Department for Food Technology and Processing of Animal Products, Faculty of Agriculture, Krste Misirkov, 2000 Stip, Macedonia 2Department for Crop Production, Faculty of Agriculture, Krste Misirkov, 2000 Stip, Macedonia
3Faculty of Tourism and Business Logistics, Krste Misirkov, 2000 Stip, Macedonia

Abstract. The purpose of this paper is to examine the impact of red sweet peppers extract on the chemical, microbiological and sensory oxidative changes presented through the parameters, acid level and properties, hydrolytic and peroxide number, during the ripening and keeping of sausage type Kulen. For this purpose, five groups of kulen sausages were made (control group I without addition of the extract, group II – 0.1 g/kg, group III – 0.2 g/kg, group IV – 0.3 /kg and group V – 0.4 g/kg extract of sweet peppers). The groups were made according to the rulebook for quality of minced meat, meat preparations and meat products no. 63 from 2013 in Macedonia. After drying and ripening sausages were stored at 4°C. At the beginning, the average initial values of free fatty acids are relatively low (from 0.20 to 0.50%), but during the production (40 day) the content of free fatty acids increased (from 2.20 to 2.50%). During the keeping and storage from 40 to day 75 in group V has the lowest increase in the content of free fatty acids and the highest in group I (2.50% 40 day to 3.78% 75 day). During the ripening, drying and storing of the sausage from day to day 70 in group V the increase in oxidative changes was the lowest (0.58 to 0.72 and from 0.72 on day 40 to 1.12 on day 75) and the highest in group I (0.65 to 1.20 and from 1.20 on day 40 to 2.20 on day75). Although there are no statistically significant differences among the tested samples during the production process and during storage of the sausage (p>0.05) the obtained lower values compared to the oxidative changes in group V are probably the result of antioxidative effect of the extract. Groups IV and V had a good cross section color of the final product compared to the other groups. During the ripening and drying, the extract of sweet pepper has no influence on pH, chemical composition and microbiological status of the final product.


Egg quality and shell colour characteristics of crosses between Araucana and Schijndelaar with highly productive White Leghorn and Rhode Island Red strains

H. Lukanov1*, A. Genchev1, A. Pavlov2

1Department of Animal Science, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Pharmacology, Animal Physiology and Physiological Chemistry, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria.

Abstract. The experiment was performed with 8 groups of 38-week-old hens (4 control and 4 experimental groups). Control groups comprised purebred White Leghorn, Schijndelaar, Rhode Island Red and Araucana hens used for formation of experimental groups of F1 crosses between White Leghorn х Schijndelaar, White Leghorn х Araucana, Rhode Island Red х Schijndelaar and Rhode Island Red х Araucana. Twenty-four eggs were collected from each group. The aim of the study was to investigate some of the primary egg quality traits and shell colour characteristics in the CIE L*a*b* system. The following parameters were determined: egg weight (g), shape index (%), albumen index, Haugh units, yolk index, yolk colour score (by La Roche scale) and average eggshell thickness (μm). The proportions of the different egg parts were calculated for each of the groups. Higher egg weights were found in breeds selected for this trait (Rhode Island Red and White Leghorn) compared to breeds in which the selection in this direction was not purposeful (Schijndelaar and Araucana) (р<0.001). Egg weight had very weak influence on egg albumen and yolk (<1% of the total dispersion of traits). The shape index of the studied eggs varied from 78.98 in purebred Araucana group to 75.36 in White Leghorn x Araucana crosses. The eggs of Schijndelaar and White Leghorn, as well as of White Leghorn х Schijndelaar and White Leghorn х Araucana crosses had normal oval shape (SI 75.3 – 76.5%), whereas the eggs of purebred Araucana and Rhode Island Red hens as well as their crosses were more oval (SI 77 – 79%). A linear negative relationship between the shape index and yolk proportion was established (L=0.068), with correlation coefficient r =-0.260. Schijndelaar hens exhibited the lowest values of the following traits: egg weight 45.90 g, albumen index 0.05, haugh units 65.13, yolk index 0.405 and yolk colour score 11.58 (p <0.001). Among the studied groups, White Leghorn eggs had the thickest eggshells (445.39 μm), while the Rhode Island Red х Araucana crosses (392.8μm) – the thinnest. The lowest relative albumen proportion was demonstrated in the eggs of Rhode Island Red х Schijndelaar crosses (56.2). The investigation of eggshell colour showed reduction of L* values from 95.49 in white-shelled eggs to 59.71 in brown-shelled eggs (р<0.001). The shell colour index (SCI) was the highest in white eggs (White Leghorn) and in blue-green eggs of Schijndelaar which had comparable colour characteristics. The lowest SCI was established in brown eggs (Rhode Island Red).


Study of physicochemical parameters of lamb meat from North East Bulgarian fine fleece breed of sheep and its crossbreds from internal breeding

R. Slavov1*, G. Mihaylova1, S. Ribarski2, P. Slavova3, D. Pamukova1

1Department of Animal Science – Ruminants and Dairy Farming, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Morphology, Physiology and Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 3Agricultural Institute, 6000 Stara Zagora, Bulgaria

Abstract. A comparative analysis of physicochemical parameters of meat from lambs of North East Bulgarian fine fleece breed and its 25% crossbreds from internal breeding with heredity from Australian merino breed and Ile de France breed. Upon starting the experiment lambs were equal and during the experiment they were placed under similar conditions of feeding and rearing. To establish the quantitative and qualitative parameters of heredity slaughter analysis were performed at 100 and 130 days of age. From the carcass of each slaughtered animal pooled samples and individual samples from m. Longissimus, m. Semitendinosus and m. Semimembranosus were taken. Studies were carried out in the Research Laboratory of the Faculty of Agriculture at Trakia University. As a result of the study the following conclusions were made: The use of the Ile de France breed in a sophisticated crossing scheme within the North East Bulgarian fine fleece breed and subsequent internal breeding relates primarily to the achievement of the highest content of protein and phospholipids in the meat of crossbred lambs from internal breeding with 25% heredity from Ile de France breed. The highest is the level of protein in all three tested muscles in the same type of crosses. Water retention and pH24 of meat from m. Longissimus, m. Semitendinosus and m. Semimembranosus of 100- and 130-day-old lambs in all three groups of lambs vary within narrow ranges and values give a reason for the meat to be described as having good quality. Internal breeding of crossbreds with 25% heredity from Australian merino breed does not affect adversely the physicochemical parameters of meat.


Effects of salt-curing on physicochemical and technological properties of Japanese quail breast meat

S. Ribarski1*, H. Lukanov2, I. Penchev3, A. Genchev2, E. Lyutskanova2

1Department of Morphology, Physiology and Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Animal Science, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
3Department of Pharmacology, Animal Physiology and Physiological Chemistry, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The purpose of the study was to establish the physico-chemical and technological properties of salt-cured breast meat from Japanese quails. It was found out that the most dramatic changes occurred during the first 4 h after the slaughter. During that period, the meat temperature decreased almost linearly from 39.8 to 10°С. The values of рН declines between post slaughter min 30 and hour 4 from 6.0 to 5.59 (Р<0,001). The curing of meat with 3% or 1.7% NaCl solutions did not have any effect on water holding capacity. After defrosting of frozen salt-cured meat, the water holding capacity was considerably improved (11 – 12.4%), consequently to loss of water. Japanese quail breast meat cured in salt solutions increased its weight by 7.7 – 8.4% on the average. After cooking, salted breast meat lost about 19 – 25% of its weight. During the first 24 h after the slaughter, L*a*b* values of m. Pectoralis increased. Within this period, lightness increased almost linearly from 41.28 to 45.51 at an increment ΔL * during the first post slaughter half an hour of 5.38 (Р<0.01) and ΔL* of 5.21 between min 30 and hour 4 (Р<0.05). Most substantial changes occurred in colour coordinates а* and b* between the 4th and 24th post slaughter hours, when they increased by 16.5 to 19.7%. Salt-curing increased significantly the values of L* and b*. The a* value was reduced (Р<0.001). The analysis of L*a*b* values of salt-cured breast meat from Japanese quails did not take into consideration the effect of salt solution concentration. The meat colour index (MCI) however demonstrated that salt-curing resulted in lightening of meat samples with influence of salt solution concentration. The curing of m. Pectoralis with 3% NaCl increased the colour index by 19.5% (Р<0.001), while curing in 1.7% NaCl resulted in considerably lighter meat – 58.6% (P<0.01).


Investigation on the technological traits of Bulgarian and imported merino wool batches

D. Pamukova*

Department of Animal Science – Ruminants and Dairy Farming, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The investigation was performed with industrial batches of merino wool originating from Bulgaria (1), Russia (2), Romania (2), Spain (1) and the Czech Republic (1). A total of 16 batches including 7 greasy wool batches, 5 clean wool batches and 4 wool sliver batches. The primary processing of wool batches (classification, washing and carding) was performed using the standard technologies applied at the textile enterprise. After the classification, the relative proportions of types vs the total amount of greasy wool were determined. Washing yields of classified greasy wool batches were established. Clean merino wool batches were submitted to the following laboratory tests: fibre diameter (μm), mean weighted length (mm), short fibre percentage (%), fatness (%), mineral matter content (%), vegetable matter content (%) and moisture (%). The parameters determined on ready wool slivers were as followed: yield (%), fibre diameter (measured with a lanameter, μm), mean weighted length (mm), length В (mm), short fibre percentage (%) and moisture (%).The two Russian wool batches were superior to all other tested batches with respect to high-grade wool content – 96.88% and 96.03%. They consisted exclusively of a single industrial class – grade 64s merino worsted wool (95.94% and 93.95% of batches, respectively). With regard to the relative share of merino worsted wool, the Bulgarian batch (40.98%) came after the Russian (96.88% and 96.03%), Romanian (batch 1) (90.23%) and Spanish wool (57.85%). Russian wool was superior to other batches with respect to washing yield (55.51%), mean weighted length (55.35 mm) and fibre cleanness (it had the lowest mineral (0.99%) and vegetable matter content (1.2%)). There were no considerable differences with respect to yield, mean weighted length and short fibre percentage between Spanish and batch 1 Romanian wool, although the mineral and vegetable matter percentages were significantly higher in Spanish clean wool. The batch from Czech and Bulgarian wool had higher fibre length, lower dustiness and less vegetable matter content than the Spanish batch, but its washing yield was lower. Compared to both Romanian batches, it occupied an intermediate position. The highest yield was established for slivers produced by Russian and Spanish wool – 80.63% and 80.12%. The yields of the other two batches were substantially lower (72.06% for Romanian and 70.54% for the mixed Bulgarian and Czech batch). The highest mean weighted fibre length was determined for slivers made from Russian wool (67.77 mm) whereas the lowest – for slivers produced from mixed Bulgarian and Czech batch (50.83 mm). The studied Russian wool batches were of greatest interest as their technological properties were concerned. Mixed with Bulgarian wool batches, they could be largely used to correct and improve the yield, short fibre length and proportion in clean wool and wool sliver.


Near Infrared Spectroscopy and aquaphotomics for monitoring changes during yellow cheese ripening

S. Atanassova*

Department of Biochemistry, Microbiology and Physics, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The aim of the study has investigation of the feasibility of Near Infrared Spectroscopy (NIRS) and aquaphotomics as a tool for the monitoring a changes during ripening of Bulgarian yellow cheese from cow milk. The cheeses were made according to Bulgarian national standard for Bulgarian yellow cheese from cow milk. Samples for spectroscopic and chemical analysis were taken after 1, 15, 20, 25, 30, 35, 40 and 45 days of ripening. Total protein, water- soluble protein, dry matter and titratable acidity were determined for all samples. NIRS measurements were performed by NIRQuest 512 spectrometer (Ocean Optics, Inc.) in the region 900-1700 nm using reflection fiber-optics probe. Aquagram coefficients were calculated. Differences in spectral data of cheese samples in the range of first overtone water region from 1300-1550 nm were found. The changes of aquagram patterns of cheese samples were significant. Investigation of aquagrams showed decreasing the free water and the number of hydrogen bonding of water molecules and increasing of solvated water in the process of ripening. Changes in aquagram patterns depend mainly on changes in titratable acidity and protein fraction in cheese during ripening. We can conclude from obtained results that NIR Spectroscopy and aquaphotomics has a potential for monitoring cheese ripening stage.